search

oyvindln / vhs-decode

Software defined VHS decoder - Fork (maybe temporary) of the ld-decode Laserdisc rf decoder
GNU General Public License v3.0
932 stars 39 forks source link

Hifi-decode with Hi8/8mm always goes NTSC even if PAL selected #95

Closed davidvankemenade closed 1 year ago

davidvankemenade commented 1 year ago

Hifi-decode always assumes the input is NTSC, even if --pal or -p is in the arguments, e.g. hifi-decode --pal -f 40 --h8 input.raw output.flac

In many cases hifi-decode still manages to work to some extent. The Left channel seems to decode well in most cases, but the Right channel contains only (or mostly) noise.

davidvankemenade commented 1 year ago

I think I've fixed this by putting in some PAL-specific lines in @VideoMem's version of hifi-decode. Pull request: https://github.com/VideoMem/ld-decode/pull/1

It turns out the R channel is in fact a difference (L-R) channel. Many test recordings still contain noise on this second channel. I think this is because the second AFM channel was added only when much mono equipment was already out there - see page 186 in https://vdoc.pub/documents/video-and-camcorder-servicing-and-technology-49gril5sruu0.